Low frequency neurostimulator for the treatment of neurological disorders

Abstract

A system for treating neurological conditions by low-frequency time varying electrical stimulation includes an electrical device for applying such low-frequency energy, in a range below approximately 10 Hz, to the patient's brain tissue. An implantable embodiment applies direct electrical stimulation to electrodes implanted in or on the patient's brain, while a non-invasive embodiment causes a magnetic field to induce electrical currents in the patient's brain.

What is claimed is:  
     
       1. A system for treating a neurological disorder in a human patient, the system comprising: 
       an implantable control module including electronic circuitry, and  
       a plurality of electrodes connected to the electronic circuitry, wherein the electrodes are adapted to be placed on the patient's brain, near the patient's brain, or in the patient's brain;  
       wherein the electronic circuitry of the control module is adapted to stimulate the patient's brain with an electrical signal having a fundamental frequency below approximately 8 Hz and a minimum of energy content at frequencies above 8 Hz.  
     
     
       2. The method of  claim 1 , wherein the electrical signal is substantially sinusoidal. 
     
     
       3. The system of  claim 1  wherein the electrical stimulation signal comprises a has a fundamental frequency between approximately 4 Hz and approximately 6 Hz. 
     
     
       4. The system of  claim 1 , wherein one electrode of the plurality of electrodes comprises a common electrode. 
     
     
       5. The system of  claim 1 , wherein the control module is implanted intracranially. 
     
     
       6. A system for treating a neurological disorder in a human patient, the system comprising: 
       an implantable control module including electronic circuitry; and  
       a plurality of electrodes connected to the electronic circuitry, wherein the electrodes are adapted to be placed on the patient's brain, near the patient's brain, or in the patient's brain;  
       wherein the electronic circuitry of the control module is adapted to stimulate the patient's brain with an electrical signal having a fundamental frequency below approximately 10 Hz and a time-varying amplitude.  
     
     
       7. The system of  claim 6 , wherein the electrical stimulation signal is applied for a duration, and the time-varying amplitude decreases over the duration. 
     
     
       8. The system of  claim 6 , wherein the electrical stimulation signal is applied for a duration, and the time-varying amplitude increases over the duration. 
     
     
       9. A method for treating a neurological disorder with a system implantable in a human patient having a brain, wherein the system comprises a control module, a sensor, and a stimulation electrode placed in, on, or near the brain, the method comprising the steps of: 
       receiving a sensed signal representative of electrical activity in the brain from the sensor;  
       identifying a neurological event in the sensed signal;  
       generating a low-frequency stimulation signal in response to the neurological event; and  
       applying the low-frequency stimulation signal to the stimulation electrode;  
       wherein the low-frequency stimulation signal has a fundamental frequency below approximately 8 Hz and a minimum of energy content at frequencies above 8 Hz.  
     
     
       10. A method for treating a neurological disorder in a human patient having a brain, the method comprising the steps of: 
       implanting a stimulation electrode in, on, or near the brain of the patient;  
       implanting a control module in the patient; and  
       causing the control module to apply a low-frequency stimulation signal to the stimulation electrode, wherein the low-frequency stimulation signal has a fundamental frequency below approximately 8 Hz and a minimum of energy content at frequencies above 8 Hz.  
     
     
       11. A method for treating a neurological disorder in a patient having a brain, the method comprising the steps of: 
       implanting a control module in the patient;  
       implanting at least one stimulation electrode in, on or near the brain of the patient;  
       generating a low-frequency stimulation signal with the signal generator, wherein the low-frequency stimulation signal has a fundamental frequency below approximately 8 Hz and a minimum of energy content at frequencies above 8 Hz; and  
       applying the low-frequency stimulation signal to the stimulation electrode.  
     
     
       12. The method of  claim 11 , wherein the low-frequency stimulation signal is substantially sinusoidal.